Wrenches secure or loosen and remove a nut from a bolt by applying torque to the nut or the head of the bolt. Conventional wrenches comprise a wrench head and an elongated wrench handle extending therefrom. With such conventional wrenches, the required torque is generated by engaging the nut or bolt within the wrench head and then applying force to the distal end of the elongated wrench handle to rotate it about the nut or bolt, thereby causing the wrench head--and the nut or bolt engaged therein--to rotate in the direction of the handle's rotation. Clockwise rotation traditionally tightens the nut and counter-clockwise motion loosened the nut. As the length of the wrench handle is increased, the user can generate more torque while reducing the amount of force applied to the distal end of the handle.
There are significant shortcomings to conventional wrenches in certain situations or environments. First, because of the length of a conventional wrench handle, conventional wrenches often cannot be used on nuts and bolts located in tight spaces. And, even if the nut or bolt can be accessed by a conventional wrench, space limitations may prevent the user from rotating the wrench handle a full rotation. In this situation, the user must disengage the wrench head, reposition the wrench and reengage the nut, and rotate the wrench handle in the appropriate direction. These time-consuming and inconvenient steps need to be repeated until the nut is completely tightened or removed from the bolt.
Another shortcoming of conventional wrenches is that they typically do not fit nuts and bolts of various sizes. Accordingly, where variously sized nuts and bolts are present or a user is not sure what size wrench a given nut or bolt requires, the user must purchase and keep handy multiple wrenches of various sizes. Or, if the wrench head is adjustable or replaceable, the user must repeatedly adjust or replace the head to finish the task at hand.
Yet another shortcoming of conventional wrenches is that they offer no way to quickly remove a nut from a bolt once the nut has been initially loosened on the bolt. With a conventional wrench, a user must continue to turn the loosened nut by (1) engaging it with the wrench head, rotating the handle and, in tight locations, disengaging and re-engaging the wrench head over the nut to rotate it again--a time-consuming and inefficient process--or (2) by disengaging the loosened nut from the wrench handle and manually turning the nut with one's fingers--an even more time-consuming and inefficient process that has the additional disadvantage of increasing the likelihood of injury to a user's knuckles and fingers.
Also, with conventional wrenches, the risk of loosing a nut is high because the wrench does not prevent a nut from falling after the nut is completely loosened from a bolt. This problem is especially prevalent when one is working on nuts and bolts that are located above an open work area, such as while working on the under side of a car.